With the non-ferrous metal prices continue to rise, more and more low-grade non-ferrous metal deposits have exploitation value. However, some of the non-ferrous metal ore bodies are symbiotic ore, and the low grade and fine grain size result in complex ore dressing process. To solve these problems, it is very necessary to continuously develop and upgrade the beneficiation technology of low-grade symbiotic ore polymetallic ore. It will be of great significance for the rational mining and sorting of polymetallic low-grade symbiotic ore. The author of the recent study Huangshaping molybdenum, bismuth, tungsten, fluorite, garnet symbiotic ore beneficiation technology to sum up, I hope the majority of the mineral counterparts have some enlightenment. The article mainly describes the mineral properties of the mines studied and the selection and application of the crushing and grinding process.
I. Study on ore properties
(1) Multi-element analysis and mineral composition of ore samples
The multi-element analysis results of the Huangshaping molybdenum, tantalum, tungsten, fluorite and garnet polymetallic ore bodies are listed in Table 1. The main mineral composition of the ore bodies and their relative contents are listed in Table 2.
Table 1 Multi-element analysis of ore samples %
Note: The unit of Ag content is g∕t.
Table 2 Main mineral composition and relative content of ore samples
It can be seen from the results of Tables 1 and 2 that the grades of tungsten, molybdenum, niobium and fluorite in the mine are very low according to the previous mineral processing design manual. With the increase of the price of mining products, these ores have a certain recycling value. However, in terms of mineral composition, the mineral content of these recyclable minerals is very low, and the amount of interfering minerals is relatively large, which makes it difficult to comprehensively recover.
(II) Study on the grain size embedding of molybdenum, tantalum, tungsten, fluorite and garnet in ore samples
The particle size analysis results of the molybdenum, tantalum, tungsten, fluorite and garnet inlays of the ore samples are shown in Table 3.
Table 3 Results of particle size analysis of molybdenum, tantalum, tungsten, fluorite and garnet inlays
As can be seen from Table 3, the minerals such as molybdenum, niobium, tungsten, fluorite, and garnet in the polymetallic ore are generally in the form of fine-grained inlays, and the thickness is unevenly embedded.
Second, the selection and application of grinding technology
(1) Test room grinding condition test
The results of the grinding and sieving test of the ore samples are shown in Table 4. The data in the table are the results measured under a grinding condition with a grinding particle size of -2 mm and a grinding concentration of 72%.
Table 4 Determination of the dissociation degree of grinding products of polymetallic ore bodies in Huangshaping Mine
It can be seen from the results in Table 4 that the Huangshaping polymetallic ore body should be finely ground to achieve a higher monomer dissociation degree. That is to say, it is suitable to use the flotation method to recover useful minerals. It is necessary to adopt a two-stage or even three-stage grinding process to facilitate the selection work.
(II) Application practice of crushing and grinding process in 1500t∕d plant of Huangshaping polymetallic mine
The crushing and grinding process of the 1500 t∕d plant of Huangshaping polymetallic mine is shown in Figure 1, and the equipment details are listed in Table 5. For comparison, the equipment breakdown of a 1500t∕d plant in a 1500t∕d plant in a tungsten-molybdenum-bismuth polymetallic ore (three-stage and one-closed) grinding (two sections and one closed circuit) is shown in Table 6. The crushing and grinding process of the 1500t∕d plant of Huangshaping Polymetallic Mine adopts a process of fragmentation, two-stage grinding and hydrocyclone grading. Compared with the conventional three-stage crushing, the process of two-stage grinding grading is much simpler. Because the two crushers and the four belt conveyors are reduced, the number of equipment stations (groups) is also small, and the number of operators required can be reduced by at least two shifts.
Fig.1 Principle of crushing and grinding principle of 1500t∕d plant of Huangshaping polymetallic mine
Table 5 Equipment list of crushing and grinding workshop of Huangshaping tungsten-molybdenum crucible 1500t∕d plant
Table 6 Equipment list of crushing and grinding workshop of a 1.25t∕d plant in a mine of Hunan
III. Comparison of operating costs of two crushing and grinding processes
The operating cost comparison results for the two crushing and grinding processes of Tables 5 and 6 are shown in Table 7.
Table 7 Comparison of operating costs of crushing and grinding workshops of two 1500t∕d plants
From the comparison results of Table 7, it can be seen that the Huangshaping tungsten-molybdenum crucible 1500t∕d plant uses a section of crushing, two-stage grinding (including one section of self-grinding), the hydrocyclone grading process, and the operating cost is higher than that of a mine in Hunan. The crushing (three sections and one closed circuit) grinding (two sections and one closed circuit) adopted by the molybdenum crucible 1500t∕d plant is low, which is conducive to reducing the production cost of the plant.
Fourth, the conclusion
According to the research, the useful grain size of various useful metal ore in molybdenum, niobium, tungsten, fluorite and garnet polymetallic ore bodies is extremely uneven, and most of them are mainly fine particles, which brings difficulties to the selection of grinding process. The three-stage (or two-stage) grinding process can achieve the purpose of basic monomer dissociation. The current development trend is toward the second-stage grinding (self-grinding with hydrocyclones).
The use of self-grinding mills in the grinding process of tungsten, molybdenum, niobium, fluorite and garnet polymetallic ore has brought new ways to reduce production costs. Its introduction not only reduces the production cost, but also reduces the use area of ​​the production site. It is a good process worthy of promotion in the polymetallic ore mining plant.
The ore lead cloth of Huangshaping molybdenum, tantalum, tungsten, fluorite and garnet polymetallic ore bodies is fine in size and is only suitable for recycling by flotation method.
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